Development and Evaluation of the Adenoid/Nasopharynx Area Ratio on Lateral Cephalograms: Correlation With Nasal Endoscopy

Objective: The clinical assessment of adenoid hypertrophy presents 2 practical challenges: (1) the need for an objective, reproducible estimate of nasopharyngeal obstruction in children when cooperation is limited and (2) the need for a reliable radiographic metric to support interdisciplinary assessment and communication between dental/orthodontic providers and otolaryngologists. To address these challenges, this study aimed to evaluate the diagnostic performance of a novel radiographic index-Adenoid/Nasopharynx Area Ratio-derived from lateral cephalometric radiographs. Study Design: Retrospective cohort study. Setting: Eye & ENT Hospital of Fudan University and affiliated orthodontic clinics, Shanghai, China (June 2023-August 2024). Methods: Consecutive children aged 2 to 14 years flagged for suspected adenoid hypertrophy during routine dental examinations were screened; eligible participants were enrolled after prespecified exclusions. De-identified data were analyzed between August and October 2024. Results: = 0.649 vs 0.603). For severe obstruction, ANAR cutoff 0.64 yielded sensitivity 70.9% and specificity 82.3% (AUC 0.834; 95% CI, 0.76-0.90); the A/N ratio AUC was 0.793. Inter-rater reliability for ANAR measurement was good (intraclass correlation coefficient [A,1] = 0.924; 95% confidence interval, 0.848-0.963; n = 30). Conclusion: Adenoid/Nasopharynx Area Ratio is a practical, reproducible planimetric index derived from lateral cephalograms that may support opportunistic upper airway assessment when imaging is already obtained for dental/orthodontic care. Nasal endoscopy remains the reference standard; ANAR is complementary, and additional radiographs solely for adenoid evaluation are not recommended.